A test for comparing the means of two samples, or the mean of one sample (or even parameter estimates) with a specified value; also known as the "Student t-test" after the pseudonym of its inventor.

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Using Mann-Whitney U instead of T-test in large sample

For my dissertation, I am examining racial differences in perceived choice and control and home and community-based services (HCBS) use in frail elders (n=659) who have moved from a nursing home into ...
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8 views

What is the appropriate statistical test to perform a difference of means within a difference of means?

Let's say I am interested in measuring the effect of three different types of interventions on test scores. Let's say the intervention is book quality, of which there are three kinds of book quality ...
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14 views

Comparing Two Count Variables Within-subjects

I have data where I asked participants to list 5 people that they thought fit a particular category. We then coded whether the people were men or women and counted the number of men and the number of ...
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8 views

test significance for frequencies

I have frequency data for six datasets (3 control samples and 3 treated samples) consisting of values for physical stiffness, when I plot the frequencies against stiffness it looks like the treated ...
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11 views

Paired or Unpaired

As a part of curriculum we had a research project to find out that turmeric is effective on oral wound. We took two groups where experimental group received turmeric only for seven days and control ...
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3 views

How to test the significance of nucleotide diversities and fixation indices between populations ?

I have four populations with >3Mio Snps and calculated nucleotide diversity as implemented in vcftools in window sizes and then took the mean of it. Now I like to know whether the differences in mean ...
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23 views

Measuring change in performance over time

I have two performance scores for multiple companies over a ten year period (10 sets of scores, one set for each year). Which would be the best method to test the hypothesis that one score has dropped ...
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1answer
33 views

Point-Biserial Correlation (r) for non homogeneous independent samples

I am performing an independent t-test, in which the independent variable is the "group" which has two values A and B representing an approach the participants used, and the dependent variable is a ...
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20 views
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10 views

Comparing means between two repeated measures AND one independent group

How do I compare the following three means? Mean of condition 1 Mean of condition 2 Mean of condition 3 But notice that we use repeated measures for conditions 1 and 2, which means we are ...
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1answer
23 views

Confidence Interval difference in means Interpretation

I have a negative confidence interval ((-35.346,-8.570) for an independent samples t-test. I understand confidence intervals for the mean. However, I am uncertain about the interpretation of the ...
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1answer
19 views

binomial test for two data populations

I have a test that has 39 questions. 20 of them have 18 possible answers and 19 of them have 3 possible answers. I built a QA system that answers 19 of the 20 and 18 of the 19 correctly. I want to ...
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1answer
103 views

Adjusting for confounders when comparing means with t test

In an article I found recently they were able to compute the difference in means of two groups (presumably with a t-test) while adjusting for confounders; they called this the aDiff (adjusted ...
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1answer
44 views

Can I use t-test to compare two groups whose event is rare (less than 1 per thousand)?

Background We ran a test marketing campaign at my company to see if our new customer segmentation has an impact on the response rate to our offer. We have created two groups to run this test ...
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59 views

Paired t-test vs Wilcoxon signed rank

I conducted a pilot study (n=14) which was evaluated retrospectively. I have four parameters with a pre-intervention and post-intervention score that I want to compare. I am wondering whether I can do ...
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19 views

Multiple t-tests on group averages vs multi-level model

I did an experiment with N participants, each tested with 10 stimuli with type 1 and 2 variants. 10 instances of each stimulus. I want to see if response to item type 1 was significantly different ...
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1answer
30 views

Can a paired t-test be used with the number of words recalled?

I recently went to a 3rd grade level science/math school exhibition, where someone had posted this data on how well people remember words, when they read it in a book vs a tablet. There were in total ...
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17 views

How high dimensional t-test in Feng's article has been obtained?

I'm reading this article and I am wondering how the authors obtained this test statistic! I need to find out how they have done this! Edit: in this article Mr. Feng just says that We propose this ...
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23 views

How to compare means of two sets when one set is a subset of another and the sample sizes are not

I have two samples containing citation counts for some publications. Of those samples one is a subset of the another. That is, subset contains some exact citation counts appearing on the other sample. ...
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14 views

Test-retest reliability

I have come across following table in a publication, where r is correlation coefficient. I could not find detailed procedures for test-retest reliability, is it any different from paired t-test ? ...
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15 views

How do I run a t-test or variance analysis on odds-ratios from multiple binary regressions in SPSS or R?

I am computing a binary logistic regression with two sexes, five age groups and two social status groups as categorical independent variables and the probability of the prevalence of a disease as ...
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2answers
37 views

Influence of HAC estimates to p-value of t-test

I have a linear regression model and because of heteroskedasticity or autocorrrelation I use HAC (Newey-West) estimates. This influences also p-values of significance t-tests of estimated coefficients ...
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1answer
29 views

paired t-test with ordinal data

Can I do a paired samples t-test when my data are ordinal? My data are reading levels at time 1 and time 2, but the data levels are A, 1 2,3,4,6,8,10, 12, 14, 20, 24, 28, 30, 34, 38, 40, 50, 60, 70, ...
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24 views

Statistical significance test for comparing machine learning algorithms

I have to find statistical significance test of machine learning algorithms SVM, Random Forest and K-NN. I am using data sets (having 10 classes). I am using rapidminer for experimentation purpose ...
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2answers
40 views

Classifier statistical significance test

Hi I have a data set say of size 450. I have created 3 datasets of this dataset i.e. 150, 300 and 450. I have used 3 classifiers on these 3 datasets and observed the performance of classifiers in ...
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36 views

Statistical testing in machine learning [closed]

I have a clarification. I am currently working as a data scientist for an IT company. I have experience in the area of NLP, ML and Big data for more than 5 years. I am from Bioinformatics background. ...
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9 views

Approach for determining winner in A/B test with more than 2 version?

I've heard people take the top performing variation (say there are 4 variations total), and then do either a t-test or a chi-square test against each of the other versions. My issue with this is ...
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23 views

Non significant main effect after controlling for covariates [duplicate]

After doing a t-test that showed a significant difference, I did an ANCOVA with 3 covariates. The ANCOVA showed no significant effect of the variable that did show a significant difference in the ...
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1answer
26 views

Degree of Freedom twice as much as it should be?

I am performing paired t-test as following: t.test(h1$pureinf_hvar, h1$pureinf_lvar, alternative="greater", Paired=T) having each column of h1 (pureinf_hvar and ...
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1answer
66 views

Can my data be assumed to be normally distributed?

I have read a lot about when to use a (paired) t-test or a Wilcoxon Signed Rank Test as the non-parametric alternative but I need your help: I have gathered some paired data and want to perform some ...
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4 views

Determining significance and power of a test with fixed sample size

I have a total population of 70K members and I 12K "kits" that I want to send out to a randomly chosen group to test if the cancellation rate is lower vs the control (so test group is 12K and control ...
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22 views

How to check if log data predict questionnaire scores?

I'm doing an analysis of an experiment and I have these source files: Log data generated by students in a platform (info stored in xAPI statements). It follows this format "user", "verb", "phase", ...
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15 views

How can I test for multivariate equivalence?

I have two sets of data and I want to test to see if they were drawn from the same population/distribution. The data sets have around 200 variables, and I want to be able to take into account the ...
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15 views

Matched pairs versus multiple t-test measurements for task performance over time

I am trying to compare performance on a task over time across one group based on initial performance, but am running into a little trouble. As background, I am examining a group of students' ...
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22 views

Which t-test to use when different sized but dependent values are in question?

I have two sets of data. At the one hand manually known correct numbers for some index values such as: ...
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4answers
535 views

How to visualize independent two sample t-test?

What are the most accepted ways to visualize the results of an independent two sample t-test? Is a numeric table more often used or some sort of plot? The goal is for a casual observer to look at the ...
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20 views

Using t-test when one of the groups is only two cases?

I apply ttest2 function in MATLAB for the following data sets: x = 21 5 6 5 2 5 2 13 28 2 y= 2 5 For this comparison whether means of those sets are equal MATLAB ...
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1answer
50 views

T-tests, manova or logistic regression - how to compare two groups?

I'd like to check whether women and men differ on those five variables, that can be correlated with each other. The groups are also not equal with 589 females and 293 males. The solutions that come ...
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1answer
39 views

Transforming models and conducting hypothesis tests

The population relationship between $y$ and $x_1, x_2, x_3$ is \begin{equation} y_t=\beta_0+\beta_1x_{1t}+\beta_{2}x_{2t}+\beta_3x_{3t}+\epsilon_{t} \end{equation} with $\epsilon_t\sim N(0,1)$. The ...
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8 views

interpreting R plot of 100 t-confidence intervals on same graph. [duplicate]

I have drawn 100 sample of size 10 from standard normal distribution using r . after that for each repetition the 95% t-confidence intervals have been plotted on the same graph paper and those ...
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2answers
58 views

Bootstrap two sample t-test - two methods

I'd like to bootstrap test a hypothesis (two sample Student's t-test). In Efron and Tibshirani 1993 p.224 there is explicit code for that: for each observation, subtract its group mean and add the ...
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37 views

Calculating epsilon for two one sided t-tests

I am using the equivalence::tost method in R. It takes a parameter epsilon, but I am unsure of how to calculate this when I require a test for non-zero Difference%. Currently, I do this by using the ...
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3answers
49 views

One tailed or two tailed situation

I understand that there is a lot of similar questions, but I can't grasp on when to use a one tailed or two tailed test when reading a example such as the one below: We suspect that test driven ...
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23 views

Hutcheson's t-test

I'm trying to find out how to perform Hutcheson's t-test for significance on Shannon-Wiener Indices. Does anybody know the formula, or how this can be performed in Excel?
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1answer
37 views

which is better/how they differ? independent t-test or simple logistic regression?

As a beginner in stats, i am wondering do simple logistic regression do what independent t-test does? and if yes, why do we still do t-test ? e.g. If there is a binary variable (e.g. smokers to ...
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1answer
44 views

What is the difference between $t$-statistic and test-statistic?

I read several posts on Cross Validated about $t$-statistic and $p$-value and I believe I understand that. But I don't understand what is test-statistic and how is it different from $t$-statistic.
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15 views

Why does the t-test assume normality? [duplicate]

T-test statistic is based on the central limit theorem which doesn't require the distribution of the sample to be normal if sample size is large. I use sample size around 200 , why should they be ...
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0answers
4 views

When is it advantageous to use the Anderson-Darling test over Student's T-test or the KS test?

I am currently running an analysis for a project and I used the A-D test to test whether two samples are drawn from the same distribution. One of my colleagues asked me what is the advantage of using ...
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1answer
29 views

What statistical analysis do I use?

My topic was: Are there significant multitasking differences between males and females. I had a total of 90 subjects (45 males and 45 females) play an online game. The game consisted of levels, and ...
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2answers
87 views

How do regression results change after standardization, as a general rule?

Based on the simulation below, it appears that standardizing all variables in a data set affects OLS results in the following ways: Coefficient estimates change Standard errors change P-values ...